Details
Originalsprache | Englisch |
---|---|
Aufsatznummer | 108488 |
Fachzeitschrift | Soil Biology and Biochemistry |
Jahrgang | 165 |
Frühes Online-Datum | 20 Nov. 2021 |
Publikationsstatus | Veröffentlicht - Feb. 2022 |
Abstract
In alpine environments, the decomposition rate of soil organic carbon (SOC) is controlled by several biotic and abiotic factors, which mostly change simultaneously and often lead to freezing and thawing cycles. However, it is highly uncertain whether the temperature sensitivity of decomposition around the freezing point of water is similar as in higher temperature ranges. In this study, we conducted a full factorial incubation experiment using soil samples from a grassland site in the Tibetan Plateau. A manipulative freeze-thaw cycle was imposed to these soils by continuously changing temperature, from −5 to 10 °C. Additional treatments included 4 levels of soil moisture at 15, 30, 60 and 90% of water-filled pore space (WFPS), and two levels of O2 concentration at 0 and 20%. We fitted the Arrhenius equation into the flux data to estimate the activation energy (Ea) and base flux rate (A) for each treatment level. Then, we predicted the dependence and sensitivity of decomposition rate (k) by implementing the Dual Arrhenius and Michaelis-Menten (DAMM) model using a Bayesian optimization approach. While soil temperature had the strongest control on SOC decomposition rate at all soil moisture and O2 levels, its intrinsic temperature sensitivity (Δk/ΔT) remained nearly constant across the entire temperature range except around 0 °C. We found that Ea was higher in nearly dry or anoxic conditions, suggesting that in these extremes more energy is required for microbial activity to take place. These intrinsic sensitivities revealed that temperature (energy) is the main factor that limits decomposition in cold environments provided that moisture and oxygen are sufficiently available. Intrinsic sensitivities with respect to soil moisture and oxygen concentration were only relevant at very narrow ranges, when soils were almost dry or partially anoxic, and small changes within these narrow ranges may lead to very strong changes in decomposition rates.
ASJC Scopus Sachgebiete
- Immunologie und Mikrobiologie (insg.)
- Mikrobiologie
- Agrar- und Biowissenschaften (insg.)
- Bodenkunde
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in: Soil Biology and Biochemistry, Jahrgang 165, 108488, 02.2022.
Publikation: Beitrag in Fachzeitschrift › Artikel › Forschung › Peer-Review
}
TY - JOUR
T1 - Sensitivity of soil respiration rate with respect to temperature, moisture and oxygen under freezing and thawing
AU - Azizi-Rad, Mina
AU - Guggenberger, Georg
AU - Ma, Yaoming
AU - Sierra, Carlos A.
N1 - Funding Information: This study was developed as part of the International Research Training Group (GRK 2309/1) Geo-ecosystems in transition on the Tibetan Plateau (TransTiP) funded by the Deutsche Forschungsgemeinschaft (DFG) .
PY - 2022/2
Y1 - 2022/2
N2 - In alpine environments, the decomposition rate of soil organic carbon (SOC) is controlled by several biotic and abiotic factors, which mostly change simultaneously and often lead to freezing and thawing cycles. However, it is highly uncertain whether the temperature sensitivity of decomposition around the freezing point of water is similar as in higher temperature ranges. In this study, we conducted a full factorial incubation experiment using soil samples from a grassland site in the Tibetan Plateau. A manipulative freeze-thaw cycle was imposed to these soils by continuously changing temperature, from −5 to 10 °C. Additional treatments included 4 levels of soil moisture at 15, 30, 60 and 90% of water-filled pore space (WFPS), and two levels of O2 concentration at 0 and 20%. We fitted the Arrhenius equation into the flux data to estimate the activation energy (Ea) and base flux rate (A) for each treatment level. Then, we predicted the dependence and sensitivity of decomposition rate (k) by implementing the Dual Arrhenius and Michaelis-Menten (DAMM) model using a Bayesian optimization approach. While soil temperature had the strongest control on SOC decomposition rate at all soil moisture and O2 levels, its intrinsic temperature sensitivity (Δk/ΔT) remained nearly constant across the entire temperature range except around 0 °C. We found that Ea was higher in nearly dry or anoxic conditions, suggesting that in these extremes more energy is required for microbial activity to take place. These intrinsic sensitivities revealed that temperature (energy) is the main factor that limits decomposition in cold environments provided that moisture and oxygen are sufficiently available. Intrinsic sensitivities with respect to soil moisture and oxygen concentration were only relevant at very narrow ranges, when soils were almost dry or partially anoxic, and small changes within these narrow ranges may lead to very strong changes in decomposition rates.
AB - In alpine environments, the decomposition rate of soil organic carbon (SOC) is controlled by several biotic and abiotic factors, which mostly change simultaneously and often lead to freezing and thawing cycles. However, it is highly uncertain whether the temperature sensitivity of decomposition around the freezing point of water is similar as in higher temperature ranges. In this study, we conducted a full factorial incubation experiment using soil samples from a grassland site in the Tibetan Plateau. A manipulative freeze-thaw cycle was imposed to these soils by continuously changing temperature, from −5 to 10 °C. Additional treatments included 4 levels of soil moisture at 15, 30, 60 and 90% of water-filled pore space (WFPS), and two levels of O2 concentration at 0 and 20%. We fitted the Arrhenius equation into the flux data to estimate the activation energy (Ea) and base flux rate (A) for each treatment level. Then, we predicted the dependence and sensitivity of decomposition rate (k) by implementing the Dual Arrhenius and Michaelis-Menten (DAMM) model using a Bayesian optimization approach. While soil temperature had the strongest control on SOC decomposition rate at all soil moisture and O2 levels, its intrinsic temperature sensitivity (Δk/ΔT) remained nearly constant across the entire temperature range except around 0 °C. We found that Ea was higher in nearly dry or anoxic conditions, suggesting that in these extremes more energy is required for microbial activity to take place. These intrinsic sensitivities revealed that temperature (energy) is the main factor that limits decomposition in cold environments provided that moisture and oxygen are sufficiently available. Intrinsic sensitivities with respect to soil moisture and oxygen concentration were only relevant at very narrow ranges, when soils were almost dry or partially anoxic, and small changes within these narrow ranges may lead to very strong changes in decomposition rates.
KW - Decomposition rate
KW - Intrinsic sensitivity
KW - Michaelis-Menten
KW - Soil carbon
KW - Soil incubation
KW - Tibetan Plateau
UR - http://www.scopus.com/inward/record.url?scp=85120617924&partnerID=8YFLogxK
U2 - 10.1016/j.soilbio.2021.108488
DO - 10.1016/j.soilbio.2021.108488
M3 - Article
AN - SCOPUS:85120617924
VL - 165
JO - Soil Biology and Biochemistry
JF - Soil Biology and Biochemistry
SN - 0038-0717
M1 - 108488
ER -